1. Technical Field
The invention relates to a device for locking and unlocking the roller shutter of a container which can be inserted into a rack and removed therefrom, the closed roller shutter being unlocked at its longitudinal edge when the container is inserted into the rack and being pulled from its closed position into its open position by means of engagement with an engagement element arranged stationarily in the rack and, when the container is removed from the rack, the roller shutter being pulled from its open position into its closed position by means of this engagement and being locked.
2. Discussion
A device of this type is, for example, used in containers which are inserted or, respectively, removed from the rack of an automated teller machine or another apparatus for the input or withdrawal of valuables. Mostly, the containers have the form of a cassette that is closed at its front side by a roller shutter. In terms of the highest possible safety, the roller shutter is only automatically opened upon insertion of the cassette into a rack in that, during insertion, it is held by cams or pins that are arranged stationarily in the rack and is thus pulled into its open position. When the container is removed, the roller shutter is pulled into its closed position according to the same principle.
A device for opening and closing as well as for unlocking and locking the roller shutter of a cassette for valuables is described in document DE 690 04 906 T2. The roller shutter is automatically unlocked in order to be opened when the cassette is inserted into the rack, and it is pulled into the closed position and automatically locked when the cassette is removed from the rack. The automatic unlocking and locking is, however, not particularly described here, and mostly electromechanical devices that operate dependent on a contact actuation and are controlled by electronic circuits are used for this purpose.
In order to limit the expense combined with the highest-possible safety, a purely mechanical unlocking and locking of the roller shutter is aimed at. When using the principle of opening the roller shutter by means of engagement with an engagement element arranged stationarily in the rack, this element being formed as a cam or pin that engages with a corresponding opening in the roller shutter, then, as a result, the roller shutter can indeed be opened and again closed by the sliding movement of the cassette but a precise coordination of the functions of the cam engagement and the unlocking or, respectively, locking of the roller shutter is difficult as several mechanical elements have to be actuated independent of one another but in exact coordination with one another during the movement of the cassette. So that the stationary cam can reliably open the roller shutter during insertion of the cassette into the rack, the roller shutter has to be unlocked shortly before the engagement of the cam. As a result of mechanical tolerances and an imprecise movement of the cassette, the point of engagement of the cam with the roller shutter may be displaced. When the cassette is pulled out of the rack, the exact point at which the cam is to be released from engagement with the roller shutter cannot be defined precisely as the roller shutter might not yet be in the exact closed position in which it can be locked.